If it is an expansion tank for the hot water heater, then almost any pressure less than about 120 psi is okay. If it is the water storage tank, and not an expansion tank then the higher pressure would have caused the pump to cycle on and off as water was used, which could have burned the points on the switch.

: Help!!!!

: I just had a new electric hot water heater installed in December. We have had problems with it ever since. We thought we had our troubles corrected when the plumber put in an expansion tank (we are on well water not city water). One day after he put in the expansion tank our pump went out and we had no water. We had a pump professional come and he said the points had burned out. He checked the expansion tank and the plumber had set the pressure to 54 PSI. Our pump pressure is 50 PSI. I know the factory sets the expansion tanks at 40 PSI. What should the pressure in the expansion tank be set at and could that have caused the points to burn out on the pump? We just had the points checked 7 days before he installed the expansion tank and they were fine. We really don't know what to do because we are getting conflicting information from each person who worked on our pump and water heater.